Java URL Connection getContainerUrl(URL url, String resourceInThatDir)

Description

get Container Url

License

Apache License

Declaration

public static URL getContainerUrl(URL url, String resourceInThatDir) 

Method Source Code

//package com.java2s;
/*//from www  .ja v  a 2 s . c o  m
 * Copyright 2015 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.io.IOException;
import java.net.JarURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

public class Main {
    public static URL getContainerUrl(URL url, String resourceInThatDir) {
        //Switching from manual parsing of jar: and file: URLs to java provided functionality.
        //The old code was breaking on any Windows path and instead of fixing it, using
        //the provided Java APIs seemed like the better option since they are already tested
        //on multiple platforms.
        boolean isJar = "jar".equals(url.getProtocol());
        if (isJar) {
            try {
                //let java handle the parsing of jar URL, no network connection is established.
                //Strips the jar protocol:
                //  jar:file:/<path to jar>!<resourceInThatDir>
                //  becomes
                //  file:/<path to jar>
                JarURLConnection connection = (JarURLConnection) url
                        .openConnection();
                url = connection.getJarFileURL();
            } catch (IOException e) {
                throw new IllegalStateException(e);
            }
        } else {
            //Remove the trailing resouceInThatDir path from the URL, thus getting the parent folder.
            String path = url.toString();
            int i = path.indexOf(resourceInThatDir);
            if (i == -1)
                throw new IllegalStateException("Resource path ("
                        + resourceInThatDir + ") not in url substring ("
                        + url + ")");
            String parent = path.substring(0, i);
            try {
                url = new URL(parent);
            } catch (MalformedURLException e) {
                throw new IllegalStateException("Resource ("
                        + resourceInThatDir
                        + ") found at invalid URL parent (" + parent + ")",
                        e);
            }
        }
        return url;
    }
}

Related

1. getCharset(URLConnection connection)
2. getCharsFromURL(URL url)
3. getChildren(URL url)
4. getConnection(URL url)
5. getConnectionResponseHeaders(URLConnection c)
6. getCookies(URLConnection conn, Map> store)
7. getDataFromServer(URL url)
8. getDefaultUrlConnection(URL url)
9. getFeedReader(URL feedUrl)